The itineraries are similar, and all include a brief stop in Ensenada, Mexico, to satisfy laws that stipulate that only U.S. owned, flagged, built and crewed ships may trade exclusively among U.S. ports. In something of a compromise, Norwegian Cruise Line's Spirit of America, (866) 234-7350, http://www.ncl.com, qualifies and offers seven-day cruises among the Hawaiian Islands, from $1,249.